Previous data has shown a correlation between Ureaplasma cultures and BPD, but I don’t think there are many data about other bacteria in the endotracheal tube. In order to know whether these data are really showing a causative relationship, I think you would need firstly a study with all intubated babies having routine cultures at the same postnatal age, and then redo this sort of analysis. Then a randomized trial of treating the positive cultures with effective antibiotics would be needed to confirm that any association may be causative, and that you can do something about it.

The technique that was used is completely new to me, using MRI, they measured the cross-sectional area of the pulmonary artery and the blood flow through the measured segment. They plot the changes in the 2 measurements during early systole, and the slope of the regression is referred to as the pulse wave velocity (PWV). They then redo the PWV after exposing the children to hypoxia. Normal children, previously studied by this group have an increase in PWV with hypoxia. In this study the preterm born children with BPD had a greater increase in their PWV than the controls. The children were all healthy, but still have what appears to be an increase in pulmonary vascular reactivity (assuming that this technique is indeed reliable), even 10 years later.